Roll out the pastry on a lightly floured surface until it is 2.5 mm (½ inch) thick and a 20 x 30 cm (8 x 12 inch) rectangle. Place the rectangle on a baking sheet lined with baking paper.
Make the filling. Beat the ricotta until it is smooth and then stir in the candied fruit, chocolate and lemon rind. Spread the mixture down the centre of the pastry, leaving a 5 cm (2 inch) border down each side.
Score the pastry lightly along each side of the filling and fold over the pastry sides to cover the edges of the filling. Brush the pastry with beaten egg and sprinkle over the flaked almonds, pressing them down lightly.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 25 minutes until risen and golden, then remove from the oven and leave to cool.
Dust the tart generously with icing sugar before serving cut in slices.